#PrintingProcesses: Digital Inkjet Printing

It’s time for a new article in our series #PrintingProcesses, in which we introduce you to all the basic – yet very important – techniques and fundamental knowledge of the print technologies we know and utilise to this day. This episode, it’s all about digital inkjet printing which belongs to the Non-Impact Printing (NIP) technology.

Printing Processes

Are you a newcomer to the world of printing and don’t know where to start? Or maybe just a devoted print enthusiast who wants to freshen up on the basics? Then you’ve come to the right place! After we took a closer look at photocopying, in this edition of #PrintingProcesses we take you into the world of digital inkjet printing which was invented in the 60s. 

Back in the Days

Between 1963 and 1970, Teletype Corporation developed the first inkjet printer in the world that was back then not a classical printer but more of a teleprinter with an integrated keyboard. Its printing performance was still low for the time and the ink could not be transferred precisely onto the paper. The result was not promising and the printer became polluted far too quickly. But it should not take long until IBM launched the first functioning inkjet printer devices, working with the continuous drop. Later on, we will come back to this technique but these printers were only available for the industry. Not until 1979, HP and Canon patented the inkjet printer simultaneously. Today inkjet printers can be almost found in any household or office. 

Now that you know a little bit of the inkjet printing history, let’s move on to its functionality. 

Drop on Demand (DOD) vs. Continuous Inkjet (CIJ)

Inkjet printing is classified in the category “digital printing” and is also called Non-Impact Printing (NIP) because the paper has no direct contact with the print substrate during the printing process. In general, inkjet printing consists of the application from ink to the printed material that is paper in most cases. Technically, inkjet printing is divided into “Drop on Demand” (DOD) and “Continuous Inkjet” (CIJ). With the former, ink is only fed through the print head on demand, meaning when a print dot is to actually be set. In contrast to that, with Continuous Inkjet the ink is generated regardless of whether or not marking is to take place. By this, unused ink is collected in the print head to be reused afterward. 

CIJ printers are used in various areas such as best-before dates, EAN codes, personalisation and much more but exclusively in industry. DOD printers, on the other hand, can be found in industry as well as in the office or home sector that makes their range of application very wide and goes from printing for passport photos to personalisation orders via the home or office area. 

Besides the distinction between DOD and CIJ, the DOD principle is also divided into thermal and piezo inkjet printing that only differs in the technique used to achieve the volume reduction. Piezo printers push the ink through a nozzle with the help of a piezo element while the ink drops are applied by targeted heating during thermal inkjet printing. The liquid inside the ink leads to the explosive formation of a vapour bubble, which in turn presses the ink through the nozzle.

The Colours of Inkjet Printers

Inkjet printing is far superior to other printing processes in terms of the quality and luminosity of the individual inks. But in order to achieve a good print result, it’s important to calibrate the individual nozzles and inks. Basically, the ink of inkjet printers is not waterproof or lightfast so that the print results are not very resistant to external influences. To counteract this, special more resistant printer inks can be used that are also known as archival inks.

The colour range of inkjet printers can be Cyan, Magenta, Yellow and Black (CMYK) or Red, Green and Blue (RGB). These colours enable the mixture of all colours needed for any print. Nevertheless, most inkjet printers also have a black printer cartridge because it’s the most commonly used printer ink. If you were to mix black from the other colours, the printer cartridges would run out very quickly. 

Summing up, digital inkjet printers have a simple construction of devices and therefore lead to low manufacturing costs. Especially on special paper, inkjet printers have reached a quality that other processes rarely achieve or at a high cost. 

Now that you got your first insights into digital inkjet printing, how it works and with which colours, learn more about other printing processes with our series #PrintingProcesses